This invention relates to magnetic disc drive assemblies of the class employing a stack of rigid discs in a standard housing profile.
Magnetic disc drive assemblies employing rigid, or hard, discs are commonly used in desktop and other computer mainframes as a principal memory for the computer. Currently, rigid disc magnetic disc drive assemblies are available in three different standard footprints, commonly known as 21/2 inch, 31/2 inch and 51/4 inch drives. These standard drives are available in several configurations, the most common being known as low-profile and half-high drives. The principal difference between a low-profile drive and a half-high drive is that a low-profile drive typically has half the number of rigid discs in the disc stack, and hence half the data storage capacity, as a half-high drive. Computer manufacturers design their computer models to accommodate one of these three standard footprints and one of the two configurations. Consequently, disc drive manufacturers produce disc drives having a form and fit meeting the standard configuration of one of the three footprints and one of the two heights.
As used herein, the term "footprint" refers to the two-dimensional plan or layout of an element at a given plane, such as the mounting layout of the element. The "footprint" of a disc drive is, therefore, the two-dimensional plan of the disc drive housing at a given plane, such as its mounting layout within the computer. The term "real estate" as used herein, refers to the three-dimensional space or volume required by an element in its operational mode. "Real estate" also refers to the space or volume required to perform an operation. Therefore, the "real estate" required for an E-block assembly is the volume required for the E-block in its full rotational pattern, as well as any space required for its installation and routine repair. The term "configuration" as used herein, refers to the three-dimensional layout or plan of an element; the "configuration" of a disc drive being the three-dimensional layout or plan of the space taken by the disc drive housing.
There is a continuing need for faster computers with greater capacity. This need is met in the disc drive industry by a combination of factors, including increasing density of data recorded on discs, increasing data transfer rates between the disc and the electronics, shortening the seek time of movement of a transducing head to a desired track on a disc, and reducing the latency to reaching a desired location on a track, among others. With increasingly improved discs, it is possible to pack more data into a given area of a disc. With increasingly more precise transducing heads, it is possible to transduce data to and from high density discs. With increasingly improved circuits, it is possible to respond to data at higher data rates. With lighter and shorter actuator arms it is possible to reduce seek times for the transducing heads. With increasingly improved spindle motors, it is possible to spin the discs faster to thereby improve data rates and reduce latency. It will be appreciated, however, that certain trade-offs are required for a given configuration of disc drives. More particularly, shorter actuator arms require smaller discs, meaning there is less disc surface on which to record data. Increased disc speed requires more power, generating more heat which requires dissipation. Given the constraint that the overall profile of the disc drive housing must conform to one of the standards, as may be required by the computer manufacturer into which the drive is to be assembled, additional trade-offs may be required to accommodate the specifications for the computer manufacturer.
The present invention is directed to a disc drive having a standard housing configuration containing a stack of rigid recording discs that are rotated at increased speed without increasing the power consumption of the drive. The present invention is also directed to a disc drive having a standard housing configuration containing a stack of rigid recording discs having smaller than standard diameters without reducing the data capacity of the drive. The present invention is also directed to a disc drive having a standard housing configuration containing a stack of rigid recording discs having smaller than standard diameters and a shorter actuator arm for reduced seek times.